Actuating cylinders commonly in use consist of a cylinder barrel which houses a movable piston and piston rod assembly. When pneumatic or hydraulic fluid pressure in a stream is applied to the cylinder barrel through a suitable port, the piston inside the cylinder barrel acts as a barrier to the fluid flow inside the barrel while fluid pressure directed to one side or other of the piston causes it and the piston rod to move. The piston remains within the confines of the barrel restrained by an end cap but the piston rod exits the cylinder barrel through the opening provided in an end cap. The free end of the piston rod may be attached to an exterior object that it is desired to move. The extended length of the device is, therefore, a column whose length equals the length of the cylinder plus the length of the cylinder rod protruding from the barrel.
Additionally, in the conventional actuating cylinder, a peripheral seal which is held by the end cap maintains fluid pressure inside the cylinder. The peripheral seal is the cause of high friction against the moving cylinder rod which results in seal wear and subsequent leakage of the fluid stream.